76 lines
2.0 KiB
Coq
76 lines
2.0 KiB
Coq
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/*
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* Copyright (c) 2001 Stephen Williams (steve@icarus.com)
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*
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* This source code is free software; you can redistribute it
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* and/or modify it in source code form under the terms of the GNU
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* General Public License as published by the Free Software
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* Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
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*/
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/*
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* This program combines two events with an event or. The tricky part
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* for the vvp target is that there is a mix of posedge and negedge
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* events.
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*/
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module ndFF ( nset, reset, Q );
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input nset; // clk negedge set Q=1
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input reset; // reset posedge set Q=0
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output Q ; // Q output
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reg Q ;
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always @(negedge nset or posedge reset)
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begin
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if (nset ==1'b0) Q = 1'b1;
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else if (reset==1'b1) Q = 1'b0;
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end
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endmodule
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module main;
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reg nset, reset;
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wire Q;
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ndFF dut(nset, reset, Q);
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initial begin
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#0 nset = 1;
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reset = 1;
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#1 nset = 0;
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#1 if (Q !== 1'b1) begin
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$display("FAILED (a) nset=%b, reset=%b, Q=%b", nset, reset, Q);
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$finish;
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end
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nset = 1;
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#1 if (Q !== 1'b1) begin
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$display("FAILED (b) nset=%b, reset=%b, Q=%b", nset, reset, Q);
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$finish;
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end
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reset = 0;
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#1 if (Q !== 1'b1) begin
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$display("FAILED (c) nset=%b, reset=%b, Q=%b", nset, reset, Q);
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$finish;
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end
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reset = 1;
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#1 if (Q !== 1'b0) begin
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$display("FAILED (d) nset=%b, reset=%b, Q=%b", nset, reset, Q);
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$finish;
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end
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$display("PASSED");
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end // initial begin
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endmodule // main
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